Transformable unmanned aerial vehicle

Abstract

An unmanned aerial vehicle (UAV) including wing sections and hinge assemblies. Each wing section includes an airfoil and a propulsion unit. The wing sections are arranged side-by-side, pivotably connected by the hinge assemblies to define an airframe module. The airframe module is transitionable between a fixed-wing state and a rotor state. In the fixed-wing state, the airframe module has an elongated shape extending between opposing, first and second ends. In the rotor state, the first end is immediately proximate the second end. With this construction, the UAV provides two distinct modes of flight (fixed-wing for low power flight, and rotor for high maneuverability flight (including hover)). The wing sections can carry solar cells and a battery. A maximum power point tracker (MPPT) can be provided for optimizing the match between the solar array and the battery. The propulsion unit can include a variable pitch propeller.

What is claimed is: 
     
         1 . An unmanned aerial vehicle comprising:
 a plurality of wing sections each including:
 an airfoil, 
 a propulsion unit, 
 wherein the wing sections are consecutively arranged side-by-side; and 
   a plurality of hinge assemblies;   wherein respective ones of the hinge assemblies pivotably connect immediately adjacent ones of the wing sections to define an airframe module;   and further wherein the airframe module is transitionable between:
 a fixed-wing state in which the airframe module has an elongated shape extending between opposing, first and second ends, the first end defined by a side of a first wing section of the plurality of wing sections and the second end defined by a side of a second wing section of the plurality of wing sections, and 
 a rotor state in which the side of the first wing section is immediately proximate the side of the second wing section. 
   
     
     
         2 . The unmanned aerial vehicle of  claim 1 , further comprising a plurality of modular pods each including a propulsion unit, and further wherein respective ones of the modular pods are mountable to an airfoil to form a corresponding one of the plurality of wing sections. 
     
     
         3 . The unmanned aerial vehicle of  claim 1 , wherein each of the wing sections further includes a plurality of photovoltaic cells maintained by the corresponding airfoil frame. 
     
     
         4 . The unmanned aerial vehicle of  claim 1 , wherein the plurality of wing sections further includes a third wing section immediately adjacent the first wing section, and the plurality of hinge assemblies includes a first hinge assembly pivotably connected the first and third wing sections, and further wherein the unmanned aerial vehicle further includes an actuator linked to the first hinge assembly and operable to articulate the first and third wing sections relative to one another in transitioning between the fixed-wing and rotor states. 
     
     
         5 . The unmanned aerial vehicle of  claim 4 , wherein the first hinge assembly includes a servo driven four-bar linkage mechanism. 
     
     
         6 . The unmanned aerial vehicle of  claim 1 , further comprising a plurality of actuator assemblies, wherein respective ones of the actuator assemblies are linked to a respective one of the plurality of hinge assemblies. 
     
     
         7 . The unmanned aerial vehicle of  claim 6 , further comprising a controller carried by the airframe module, wherein the controller is electronically connected to each of the plurality of actuator assemblies and is programmed to prompt operation of the plurality of actuator assemblies to automatically transition the airframe module between the fixed-wing and rotor states. 
     
     
         8 . The unmanned aerial vehicle of  claim 1 , wherein the plurality of wing sections includes exactly four wing sections, and further wherein with operation of the propulsion units in the fixed-wing state, the unmanned aerial vehicle experiences flight as fixed wing aircraft, and even further wherein with the operation of the propulsion units in the rotor state, the unmanned vehicle experiences flight as quad-copter. 
     
     
         9 . The unmanned aerial vehicle of  claim 8 , wherein the propulsion unit of each of the plurality of wing sections includes a propeller, and further wherein the airframe module is configured such that the propellers of immediately adjacent ones of the wing sections rotate in opposite directions. 
     
     
         10 . The unmanned aerial vehicle of  claim 1 , wherein the propulsion unit of the first wing segment includes a motor and a propeller rotatably driven by a shaft of the motor, and further wherein a pitch of the propeller relative to the motor shaft is variable. 
     
     
         11 . The unmanned aerial vehicle of  claim 10 , wherein the propulsion unit of the first wing segment further includes a propeller pitch control mechanism operable to alter the pitch of the propeller relative to the motor shaft. 
     
     
         12 . The unmanned aerial vehicle of  claim 1 , wherein the propulsion unit of the first wing segment includes a housing supporting a motor and a propeller rotatably driven by a shaft of the motor, and further wherein the housing is releasably mounted to the corresponding airfoil frame. 
     
     
         13 . The unmanned aerial vehicle of  claim 12 , wherein a connection between the propulsion unit and the airfoil frame of the first wing section permits the housing to be selectively secured to the airfoil frame at a plurality of locations relative to a leading end of the airfoil frame, and further wherein a center of gravity of the first wing section is varied as a function of the selected location of the housing relative to the leading end. 
     
     
         14 . The unmanned aerial vehicle of  claim 1 , wherein each wing section further includes at least one battery, a plurality of photovoltaic cells and a maximum power point tracker (MPPT) module. 
     
     
         15 . The unmanned aerial vehicle of  claim 14 , further comprising a controller electronically connected to and controlling operation of each of the MPPT modules. 
     
     
         16 . The unmanned aerial vehicle of  claim 15 , wherein the controller is an autopilot controller carried by one of the plurality of wing sections. 
     
     
         17 . The unmanned aerial vehicle of  claim 1 , wherein the unmanned aerial vehicle is configured to self-perform a transition from the rotor state to the fixed-wing state while airborne, and to self-perform a transition from the fixed-wing state to the rotor state while airborne.